Filament swapping in three-dimensional printing

ABSTRACT

An extruder is fitted with a connector for coupling and decoupling with a filament feed source, such as a filament tube. When connected, the extruder and filament tube are aligned to define a feed path for a filament. A tool rack includes a plurality of filament tubes secured within respective openings. The tool rack may facilitate coupling and decoupling operations between the extruder and filament sources. For example, the tool rack may define an insertion path that engages a filament tube during insertion, and that secures the filament tube against an excursion from the insertion path. The extruder may disengage the coupling by initiating a motion along the insertion path and then moving off of the insertion path to decouple the filament tube and the extruder. In this manner, filaments may be swapped through engaging and disengaging the extruder with different filament tubes on the tool rack.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. §119(e) of U.S.Provisional Application No. 62/273,307 filed on Dec. 30, 2015, theentire contents of which are hereby incorporated by reference.

TECHNICAL FIELD

The disclosure relates to filament swapping in three-dimensionalprinting, and to a tool rack for filament tubes.

BACKGROUND

In three-dimensional printing processes, filaments are extruded tofabricate objects. As the supply of filament is depleted during thefabrication of an object the filament moving through an extruder isswapped during the three-dimensional printing process. Similarly,filament swapping occurs as a different color or type of material isrequired during the three-dimensional printing process. Filamentswapping can be disruptive to the three-dimensional printing process,resulting in inefficiencies in the process.

SUMMARY

Improved filament swapping in three-dimensional printing may beadvantageous. An extruder may be fitted with a connector for coupling toand decoupling from a filament feed source such as a filament tube witha mating connector. When engaged through these connectors, the extruderand filament tube are aligned, defining a feed path for a filamentthrough the filament tube and the extruder. A tool rack may include aplurality of filament tubes (e.g., filament tubes having differentcolored filaments) secured within respective openings in the tool rack.The tool rack may be configured to facilitate coupling and decouplingoperations between the extruder and filament sources. For example, thetool rack may define respective insertion paths, with each insertionpath engageable with one of the filament tubes during insertion tosecure the filament tube against an excursion from the insertion path.Thus, the extruder or other robotic system may initiate motion along theinsertion path to couple the filament tube and the extruder and thenmove off of the insertion path to disengage the filament tube from theextruder. In this manner, filaments may be swapped through engaging anddisengaging the extruder with different filament tubes on the tool rackduring a three-dimensional print.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of the devices,systems, and methods described herein will be apparent from thefollowing description of particular embodiments thereof, as illustratedin the accompanying drawings. The drawings are not necessarily to scale,emphasis instead being placed upon illustrating the principles of thedevices, systems, and methods described herein.

FIG. 1 is a block diagram of a three-dimensional printer.

FIG. 2 is a schematic representation of an extruder coupled to afilament tube.

FIG. 3 is a front view of a tool rack.

FIG. 4 is a top view of a tool rack.

FIG. 5 is a schematic representation of tool paths of an extruder forfilament swapping in three-dimensional printing.

FIG. 6 is a flow chart of a method for filament swapping inthree-dimensional printing.

FIG. 7 is a flow chart of a method for filament swapping inthree-dimensional printing.

DETAILED DESCRIPTION

The embodiments will now be described more fully hereinafter withreference to the accompanying figures, in which preferred embodimentsare shown. The foregoing may, however, be embodied in many differentforms and should not be construed as limited to the illustratedembodiments set forth herein.

All documents mentioned herein are hereby incorporated by reference intheir entirety. References to items in the singular should be understoodto include items in the plural, and vice versa, unless explicitly statedotherwise or clear from the context. Grammatical conjunctions areintended to express any and all disjunctive and conjunctive combinationsof conjoined clauses, sentences, words, and the like, unless otherwisestated or clear from the context. Thus, the term “or” should generallybe understood to mean “and/or” and so forth.

Recitation of ranges of values herein are not intended to be limiting,referring instead individually to any and all values falling within therange, unless otherwise indicated herein, and each separate value withinsuch a range is incorporated into the specification as if it wereindividually recited herein. The words “about,” “approximately,” or thelike, when accompanying a numerical value, are to be construed asindicating a deviation as would be appreciated by one of ordinary skillin the art to operate satisfactorily for an intended purpose. Ranges ofvalues and/or numeric values are provided herein as examples only, anddo not constitute a limitation on the scope of the describedembodiments. The use of any and all examples or exemplary language(“e.g.,” “such as,” or the like) provided herein, is intended merely toilluminate better the embodiments and does not pose a limitation on thescope of the embodiments or the claims. No language in the specificationshould be construed as indicating any unclaimed element as essential tothe practice of the disclosed embodiments.

In the following description, it is understood that terms such as“first,” “second,” “top,” “bottom,” “above,” “below,” “up,” “down,” andthe like, are words of convenience and are not to be construed aslimiting terms unless specifically stated.

The following description emphasizes three-dimensional printers usingfused deposition modeling or similar techniques where a bead of materialis extruded in a layered series of two dimensional patterns as “roads”or “paths,” to form a three-dimensional object from a digital model. Itwill be understood, however, that numerous additive fabricationtechniques are known in the art including, without limitation, multijetprinting, stereolithography, Digital Light Processor (“DLP”)three-dimensional printing, selective laser sintering, and so forth.Such techniques may benefit from the systems and methods describedbelow, and all such printing technologies are intended to fall withinthe scope of this disclosure, and within the scope of terms used hereinsuch as “printer,” “three-dimensional printer,” “fabrication system,”and so forth, unless a more specific meaning is explicitly provided orotherwise clear from the context.

FIG. 1 is a block diagram of a three-dimensional printer. In general, aprinter 100 may include a build platform 102, a conveyor 104, anextruder 106, an x-y-z positioning assembly 108, and a controller 110that cooperate with one another to fabricate an object 112 within aworking volume 114 of the printer 100.

The build platform 102 may include a surface 116 that is rigid andsubstantially planar. The surface 116 may support the conveyer 104 toprovide a fixed, dimensionally and positionally stable platform on whichto build the object 112.

The build platform 102 may include a thermal element 130 that controlsthe temperature of the build platform 102 through one or more activedevices 132 such as thermoelectric heating and/or cooling devices (e.g.,resistive elements that convert electrical current into heat, Peltiereffect devices that can create a heating or cooling affect, andcombinations thereof). Accordingly, the thermal element 130 may be aheater that provides active heating to the build platform 102, a coolingelement that provides active cooling to the build platform 102, or acombination of these. The heater 130 may be coupled in a communicatingrelationship with the controller 110 for the controller 110 tocontrollably impart heat to or remove heat from the surface 116 of thebuild platform 102. Thus, for example, the thermal element 130 mayinclude an active cooling element positioned within or adjacent to thebuild platform 102 to controllably cool the build platform 102.

It will be understood that a variety of other techniques mayadditionally, or alternatively, be employed to control a temperature ofthe build platform 102. For example, the build platform 102 may use agas cooling or gas heating device such as a vacuum chamber in aninterior thereof, which may be quickly pressurized to heat the buildplatform 102 or vacated to cool the build platform 102 as desired. Asanother non-exclusive example, a stream of heated or cooled gas may beapplied directly to the build platform 102 before, during, and/or aftera build process.

The conveyer 104 may include a sheet 118 of material that moves in apath 120 through the working volume 114. Within the working volume 114,the path 120 may pass proximal to the surface 116 of the build platform102—that is, resting directly on or otherwise supported by the surface116—to provide a rigid, positionally stable working surface for a build.It will be understood that, while the path 120 is depicted as aunidirectional arrow, the path 120 may be bidirectional, such that theconveyer 104 can move, for example, in either of two opposing directionsthrough the working volume 114. It will also be understood that the path120 may curve in any of a variety of ways, such as by looping underneathand around the build platform 102, over and/or under rollers, or arounddelivery and take up spools for the sheet 118 of material. Thus, whilethe path 120 may be generally (but not necessarily) uniform through theworking volume 114, the conveyer 104 may move in any direction suitablefor moving completed items from the working volume 114. The conveyor 104may, additionally or alternatively, include a motor or other similardrive mechanism (not shown) coupled to the controller 110 to controlmovement of the sheet 118 of material along the path 120. Various drivemechanisms are described in further detail below.

In general, the sheet 118 may be formed of a flexible material such as amesh material, a polyamide, a polyethylene terephthalate (commerciallyavailable in bi-axial form as MYLAR), a polyimide film (commerciallyavailable as KAPTON), or any other suitably strong polymer or othermaterial. The sheet 118 may have a thickness of about three to aboutseven thousandths of an inch, or any other thickness that permits thesheet 118 to follow the path 120 of the conveyer 104. For example, withsufficiently strong material, the sheet 118 may have a thickness ofabout one to about three thousandths of an inch. The sheet 118 mayfurther, or instead, include sections of rigid material joined byflexible links.

A working surface of the sheet 118 (e.g., an area on the top surface ofthe sheet 118 within the working volume 114) may be treated to assistwith adhesion of build material to the surface 118 and/or to facilitateremoval of completed objects from the surface 118. For example, theworking surface may be abraded or otherwise textured (e.g., withgrooves, protrusions, and the like) to improve adhesion between theworking surface and the build material.

A variety of chemical treatments may be used on the working surface ofthe sheet 118 of material to facilitate build processes as describedherein. For example, the chemical treatment may include deposition ofmaterial that can be chemically removed from the conveyer 104 by use ofwater, solvents, or the like. This may facilitate separation of acompleted object from the conveyer by dissolving the layer of chemicaltreatment between the object 112 and the conveyor 104. The chemicaltreatments may include deposition of a material that easily separatesfrom the conveyer such as a wax, mild adhesive, or the like. Thechemical treatment may include a detachable surface such as an adhesivethat is sprayed onto the conveyer 104 prior to fabrication of the object112.

In one aspect, the conveyer 104 may include a sheet of disposable,one-use material fed from a dispenser and consumed with each successivebuild.

In one aspect, the conveyer 104 may include a number of differentworking areas with different surface treatments adapted for differentbuild materials or processes. For example, different areas may havedifferent textures (e.g., smooth, abraded, grooved, etc.). Additionally,or alternatively, different areas may be formed of different materials.Further, or instead, different areas may have or receive differentchemical treatments. Thus, it should be appreciated that a singleconveyer 104 may be used in a variety of different build processes byselecting the various working areas as needed or desired.

The extruder 106 may include a chamber 122 in an interior thereof toreceive a build material. The build material may, for example, includeacrylonitrile butadiene styrene (“ABS”), high-density polyethylene(“HDPL”), polylactic acid, or any other suitable plastic, thermoplastic,or other material that can usefully be extruded to form athree-dimensional object. The extruder 106 may include an extrusion tip124 defining an exit port with a circular, oval, slotted or othercross-sectional profile that extrudes build material in a desiredcross-sectional shape.

The extruder 106 may include a heater 126 to melt build materials (e.g.,thermoplastic material) within the chamber 122 for extrusion through theextrusion tip 124 in melted form. While illustrated in block form, itwill be understood that the heater 126 may include, e.g., coils ofresistive wire wrapped about the extruder 106, one or more heatingblocks with resistive elements to heat the extruder 106 with appliedcurrent, an inductive heater, or any other arrangement of heaterssuitable for creating heat within the chamber 122 to melt the buildmaterial for extrusion. The extruder 106 may also, or instead, include amotor 128 to push the build material into the chamber 122, through theextrusion tip 124, or a combination thereof.

In general operation (and by way of example rather than limitation), abuild material, such as ABS plastic in filament form, may be fed intothe chamber 122 from a spool by the motor 128, melted by the heater 126,and extruded from the extrusion tip 124. By controlling processparameters (e.g., one or more of a rate of the motor 128 and thetemperature of the heater 126) the build material may be extruded at acontrolled volumetric rate. It will be understood that a variety oftechniques may be employed to deliver build material at a controlledvolumetric rate, which may depend upon the type of build material, thevolumetric rate desired, and any other factors. All such techniques thatmight be suitably adapted to delivery of build material for fabricationof a three-dimensional object are intended to fall within the scope ofthis disclosure. Other techniques may be employed for three-dimensionalprinting, including extrusion-based techniques using a build materialthat is curable and/or a build material of sufficient viscosity toretain shape after extrusion.

The x-y-z positioning assembly 108 may generally be movable tothree-dimensionally position the extruder 106 and the extrusion tip 124within the working volume 114. Thus, for example, by controlling thevolumetric rate of delivery for the build material and the x, y, zposition of the extrusion tip 124, the object 112 may be fabricated inthree dimensions by depositing successive layers of material intwo-dimensional patterns derived (e.g., two-dimensional patterns derivedfrom cross-sections of a computer model or other computerizedrepresentation of the object 112). The x-y-z positioning assembly 108may, for example, include a number of stepper motors 109 to controlindependently a position of the extruder within the working volume alongeach of an x-axis, a y-axis, and a z-axis. More generally, the x-y-zpositioning assembly 108 may include, without limitation, variouscombinations of stepper motors, encoded DC motors, gears, belts,pulleys, worm gears, threads, and the like. Any such arrangementsuitable for controllably positioning the extruder 106 within theworking volume 114 may be adapted to use with the printer 100 describedherein.

By way of example and not limitation, the conveyor 104 may be affixed toa bed that provides x-y positioning within the plane of the conveyor104, while the extruder 106 can be independently moved along a z-axis.Additionally, or alternatively, the conveyor 104 may be x, y, and zpositionable, and the extruder 106 may be, optionally, stationary.Further, or instead, the extruder 106 may be x, y, and z positionablewhile the conveyer 104 remains fixed (relative to the working volume114). In yet another example, the conveyer 104 may, by movement of thesheet 118 of material, control movement in one axis (e.g., the y-axis),while the extruder 106 moves in the z-axis as well as one axis in theplane of the sheet 118. Thus, in certain instances, the conveyor 104 maybe attached to and move with at least one of an x-axis stage (thatcontrols movement along the x-axis), a y-axis stage (that controlsmovement along a y-axis), and a z-axis stage (that controls movementalong a z-axis) of the x-y-z positioning assembly 108. More generally,any arrangement of motors and other hardware controllable by thecontroller 110 may serve as the x-y-z positioning assembly 108 in theprinter 100 described herein. Still more generally, while an x, y, zcoordinate system may serve as a convenient basis for positioning withinthree dimensions, any other coordinate system or combination ofcoordinate systems may also or instead be employed, such as a positionalcontroller and assembly that operates according to cylindrical orspherical coordinates.

The controller 110 may be electrically coupled in a communicatingrelationship with the build platform 102, the conveyer 104, the x-y-zpositioning assembly 108, and the other various components of theprinter 100. In general, the controller 110 is operable to control thecomponents of the printer 100, such as the build platform 102, theconveyer 104, the x-y-z positioning assembly 108, and any othercomponents of the printer 100 described herein to fabricate the object112 from the build material. The controller 110 may include anycombination of software and/or processing circuitry suitable forcontrolling the various components of the printer 100 described hereinincluding, without limitation, microprocessors, microcontrollers,application-specific integrated circuits, programmable gate arrays, andany other digital and/or analog components, as well as combinations ofthe foregoing, along with inputs and outputs for transceiving controlsignals, drive signals, power signals, sensor signals, and the like. Inone aspect, the controller 110 may include a microprocessor or otherprocessing circuitry with sufficient computational power to providerelated functions such as executing an operating system, providing agraphical user interface (e.g., to a display coupled to the controller110 or printer 100), convert three-dimensional models into toolinstructions, and operate a web server or otherwise host remote usersand/or activity through a network interface 136 described below.

A variety of additional sensors may be usefully incorporated into theprinter 100 described above. These are generically depicted as sensor134 in FIG. 1, for which the positioning and mechanical/electricalinterconnections with other elements of the printer 100 will depend uponthe type and purpose of the sensor 134 and will be readily understoodand appreciated by one of ordinary skill in the art. The sensor 134 mayinclude a temperature sensor positioned to sense a temperature of thesurface of the build platform 102. This may, for example, include athermistor embedded within or attached below the surface of the buildplatform 102. This may also or instead include an infrared detectordirected at the surface 116 of the build platform 102 or the sheet 118of material of the conveyer 104. Other sensors that may be usefullyincorporated into the printer 100 as the sensor 134 include, withoutlimitation, a heat sensor, a volume flow rate sensor, a weight sensor, asound sensor, and a light sensor. Certain more specific examples areprovided below by way of example and not of limitation.

The sensor 134 may include a sensor to detect a presence (or absence) ofthe object 112 at a predetermined location on the conveyer 104. This mayinclude an optical detector in a beam-breaking configuration to sensethe presence of the object 112 at a location such as an end of theconveyer 104. This may also or instead include an imaging device andimage processing circuitry to capture an image of the working volume 114and analyze the image to evaluate a position of the object 112. Thissensor 134 may be used, for example, to ensure that the object 112 isremoved from the conveyor 104 prior to beginning a new build at thatlocation on the working surface (e.g., the surface 116 of the buildplatform 102). Thus, the sensor 134 may be used to determine whether anobject is present that should not be, or to detect when an object isabsent, or a combination thereof. The feedback from this sensor 134 maybe used by the controller 110 to issue processing interrupts orotherwise control operation of the printer 100.

The sensor 134 may include a sensor that detects a position of theconveyer 104 along the path. This information may be obtained, forexample, from an encoder in a motor that drives the conveyer 104, orusing any other suitable technique such as a visual sensor andcorresponding fiducials (e.g., visible patterns, holes, or areas withopaque, specular, transparent, or otherwise detectable marking) on thesheet 118.

The sensor 134 may include a heater (e.g., a radiant heater or forcedhot air) to heat the working volume 114 to maintain the object 112 at afixed, elevated temperature throughout a build. The sensor 134 may also,or instead, include a cooling element to maintain the object 112 at apredetermined sub-ambient temperature throughout a build. It should beappreciated that a heater included in the sensor 134 may be instead of,or in addition to, the thermal element 130.

The sensor 134 may also, or instead, include at least one video camera.The video camera may generally capture images of the working volume 114,the object 112, or any other hardware associated with the printer 100.The video camera may provide a remote video feed through the networkinterface 136. In such instances, the feed may be available to remoteusers through a user interface maintained, for example, by remotehardware, or, further or instead, the feed may be available within a webpage provided by a web server hosted by the three-dimensional printer100. Thus, in certain implementations, there is a user interface adaptedto present a video feed from at least one video camera of athree-dimensional printer to a remote user through a user interface.

The sensor 134 may also, or instead, include more complex sensing andprocessing systems or subsystems, such as a three-dimensional scannerusing optical techniques (e.g., stereoscopic imaging, or shape frommotion imaging), structured light techniques, or any other suitablesensing and processing hardware that might extract three-dimensionalinformation from the working volume 114. In some instances, the sensor134 may include a machine vision system that captures images andanalyzes image content to obtain information about the status of a job,working volume 114, or an object 112 therein. The machine vision systemmay support a variety of imaging-based automatic inspection, processcontrol, and/or robotic guidance functions for the three-dimensionalprinter 100 including, without limitation, pass/fail decisions, errordetection (and corresponding audible or visual alerts), shape detection,position detection, orientation detection, collision avoidance, andcombinations thereof.

The printer 100 may include other hardware 135, which may be, forexample, input devices including any one or more of the following: akeyboard, a touchpad, a mouse, switches, dials, buttons, and motionsensors. Additionally, or alternatively, the other hardware 135 may be,for example, output devices including any one or more of the following:a display, a speaker or other audio transducer, and light emittingdiodes. Other hardware 135 may also, or instead, include a variety ofcable connections and/or hardware adapters for connecting, for example,to external computers, external hardware, external instrumentation dataacquisition systems, and combinations thereof.

The printer 100 may include, or be connected in a communicatingrelationship with, the network interface 136. The network interface 136may include any combination of hardware and software suitable forcoupling the controller 110 and other components of the printer 100 to aremote computer in a communicating relationship through a data network.By way of example and not limitation, this may include electronics for awired or wireless Ethernet connection operating according to the IEEE802.11 standard (or any variation thereof), or any other short or longrange wireless networking components. This may include hardware forshort range data communications such as Bluetooth or an infraredtransceiver, which may be used to couple into a local area network thatis, in turn, coupled to a data network such as the Internet. This mayalso, or instead, include hardware/software for a WiMAX connection or acellular network connection (using, e.g., CDMA, GSM, LTE, or any othersuitable protocol or combination of protocols). The controller 110 maybe configured to control participation by the printer 100 in any networkto which the network interface 136 is connected, such as by autonomouslyconnecting to the network to retrieve printable content, or respondingto a remote request for status or availability.

Devices, systems, and methods for filament swapping in three-dimensionalprinting will now be described. In general, techniques are described forautomatic filament swapping and loading before and during athree-dimensional print. As described in greater detail below, this canbe facilitated through the inclusion of filament tubes having connectorsand extruders having corresponding connectors. For example, if eachfilament tube terminates with a ring magnet and a similar ring magnet ismounted on the extruder, a concentric mating can be achieved if thesetwo components come within a predetermined distance of one another.

Devices, systems, and methods for filament swapping in three-dimensionalprinting may also, or instead, include a tool rack, such as one made ofsheet metal, plastic, or a combination thereof, that can hold multiplefilament tubes, for example, off to the side of a gantry for an extruderin a three-dimensional printer. As described in greater detail below, ifthe extruder passes underneath the filament tube, the extruder andfilament tube can snap together to form an engagement. As also describedin greater detail below, to disconnect a filament tube, the extruder canmove in a predetermined manner with respect to an insertion path definedby the tool rack such that a resulting force can disengage the filamenttube from the extruder.

There are many advantageous uses of the devices, systems, and methods offilament swapping described herein. For example, filament swappingaccording to the devices, systems, and methods described herein canfacilitate using different colors in one print (e.g., where the extrudercan swap between each automatically). Additionally, or alternatively,the same color may be loaded on multiple filament tubes to increase thelikelihood that there is enough material to finish a print.Implementations may also, or instead, facilitate automatic filamentloading. For example, the printer can hold multiple colored spools offilament and allow a user to simply select which color to use during aprint. Further, or in the alternative, the printer may load a colorautomatically and begin printing.

FIG. 2 is a schematic representation of an extruder coupled to afilament tube. Specifically, a device 200 may include an extruder 210, arobot 230 to position the extruder 210, and a filament tube 240.

The extruder 210 may include a first fixture 212 having a firstconnector 214. The first fixture 212 may include a housing of theextruder 210, a portion thereof, or an element connected to the extruder210. The first connector 214 may include a first magnet (e.g., a ringmagnet). While fixed magnets can usefully provide a mechanical couplingthat self-aligns to a desired position, it will be understood that otherforms of coupling may also or instead be used. For example, a magneticcoupling may be augmented with one or more self-aligning mechanicalfeatures such as positive or negative detents, kinematic couplings, orcombinations thereof. The first connector 214 may also, or instead, useother alignment and engagement mechanisms, including a variety of activeand passive mechanisms such as grooves, notches, arms, slots, levers,threaded rods, electromagnets, and combinations thereof.

The extruder 210 may include a drive gear 216 to advance a filament 202through the extruder 210. In certain instances, the extruder 210 mayinclude a heat source 218 to melt the filament 202 into a melted statein the extruder 210. Additionally, or alternatively, the extruder 210may define an extrusion port 220. It should be appreciated that, in use,the filament 202 in the melted state may be extruded through theextrusion port 220, which may be located, for example, on a nozzle ofthe extruder 210.

The robot 230 may be coupled to the extruder 210 and movable verticallyand horizontally in a three-dimensional printing process. The robot 230may, for example, include an x-y-z positioning system of athree-dimensional printer.

The filament tube 240 may include a second fixture 242 having a secondconnector 244. The second connector 244 may be positioned, for example,to secure the filament tube 240 in a predetermined alignment with theextruder 210 through a coupling between the first connector 214 and thesecond connector 244. The filament tube 240 and the extruder 210, in thepredetermined alignment, may define a feed path 204. For example, thefeed path 204 may extend through the filament tube 240 and the extruder210. It will be understood that the filament tube 240 may constrain andguide the filament through the second fixture 242 into the extruder 210.For example, the filament tube 240 may include an extended guide such asa guide tube from a build material source (e.g., a spool of filament) tothe second connector 244. As a further or alternative example, thefilament tube 240 may define a cylindrical opening through the secondconnector 244. More generally, the filament tube 240 may include anycomponent or group of components coupled to the second connector 244 andguiding a build material from a source to the extruder 210 (when coupledto the second connector 244).

The second fixture 242 may include, for example, an end of the filamenttube 240. In certain instances, the second fixture 242 may also orinstead be discrete component connected to the filament tube 240. Ininstances in which the first connector 214 includes a first magnet, thesecond connector 244 may include a second magnet (e.g., a ring magnet).Thus, in certain aspects, the coupling may include a magnetic couplingbetween the first magnet and the second magnet. While the firstconnector 214 and the second connector 244 have been described asincluding a first magnet and a second magnet, respectively, it should beappreciated that the first connector 214 and the second connector 244may also or instead include other types of connecting elements orfeatures including, but not limited to, clamps, clips, male/femaleconnectors, snap-fit parts, friction fit parts, suction, hook and loop,latches, keys, pins, screws, sliders, and combinations thereof. Incertain implementations, the second fixture 242 may include a one-waygear to engage the filament within the second fixture 242 and retain thefilament even when the filament is not engaged with a drive motor of anextruder. The second fixture 242 may assist in control of dispensingfilament in a three-dimensional printing process as contemplated hereinand, thus, may include a pre-heater, a filament detector, andcombinations thereof.

The device 200 may be engageable with a tool rack, such as any one ormore of those described herein. The tool rack may, for example, definean opening and an insertion path. Continuing with this example, thesecond fixture 242 may be positionable in the opening along theinsertion path—e.g., an insertion path to receive and secure the secondfixture 242. Specifically, the tool rack may secure the second fixture242 positioned in the opening against an excursion by the robot 230 fromthe insertion path to disengage the coupling between the first connector214 and the second connector 244 to separate the filament tube 240 fromthe extruder 210. In other words, in certain aspects, when the robot 230makes such an excursion, this breaks the coupling between the firstconnector 214 and the second connector 244 to separate the filament tube240 from the extruder 210. The tool rack may be positioned within anoperating envelope of the robot 230 for positioning the extruder 210.For example, the tool rack may be positioned within a build volume of athree-dimensional printer, or in an adjacent area or container wherefabrication does not take place, but where tools and other print-relatedresources can be stored.

The device 200 may further include or be in communication with aprocessor 206 configured to determine one or more properties of one ormore filaments 202 included in respective filament tubes 240.Additionally, or alternatively, the processor 206 may be configured tocreate tool instructions for fabricating an object using combinations ofthe one or more filaments 202 based on the one or more propertiesdetermined by the processor 206. The one or more properties of thefilament 202 may include a color, a material type, a texture, amechanical property (e.g., hardness, elasticity, etc.), and combinationsthereof.

The device 200 may include a tag 208 on or associated with each supplyof build material (e.g., on a filament spool), on the filament tube 240,on the second connector 244, on the tool rack, or at any other suitablelocation where the tag 208 can be scanned for information associatedwith one of the build materials. The tag 208 may identify the associatedbuild material, or provide other information for use by the processor206 in determining one or more properties of one or more filaments 202included in the respective filament tubes 240. The tag 208 may include,for example, one or more of a microchip, a quick response (QR) code, anda radio frequency identification (RFID) tag. In certain aspects, theprocessor 206 may determine the color or type of filament 202 associatedwith each filament tube 240 (e.g., using a tagged spool/cartridge,tagged filament tube, manual entry for each filament tube 240 by a userthrough a user interface, or a combination thereof). The processor 206may create appropriate tool instructions to fabricate a multi-color ormulti-material object by swapping filaments 202. In certain aspects, thetool instructions provide for swapping filaments 202 at specific pointsduring a build. Such points during the build may be, for example, duringone or more of the printing of infill to facilitate transition regionshaving color changes, material changes, and leaking of melted filament.

In certain aspects, the tag 208 may be removable and replaceable. Forexample, in instances in which the second connector 244 can be unloadedand reloaded with different filaments, the second connector 244 mayinclude a location where the tag 208 can be affixed, using an adhesive,a magnet, or any other mechanism to place the tag 208 in a location thatpermits reading by a machine reading tool, a human, or both. A bulksupply of a build material, such as a spool of filament, may be packagedwith a tag 208 to be used for temporarily labeling the second connector244 in this manner.

The processor 206 may send print suggestions to a user based on the typeand/or availability of filament included in the filament tubes 240,These print suggestions can include automatically making arecommendation to a user of objects to print (e.g., from a library ofavailable models) based at least in part on an amount of filament/buildmaterial remaining in a system. For example, a model may be selectedbased on an amount of available material, a type of available material,and one or more preferences of a user. The processor 206 may also, orinstead, recommend or make changes to slice settings (e.g., depositionrate, infill, etc.) based on an amount of filament/build materialremaining in a system.

FIG. 3 is a front view of a tool rack. A tool rack 300 may define one ormore openings 350. A filament tube 340 may be held in each respectiveopening 350. The filament tube 340 may include a second fixture 342 anda second connector 344. In use, a filament 302 may be disposed in thefilament tube 340. The opening 350 may receive and secure the secondfixture 342 of the filament tube 340. For example, a robot thatpositions an extruder of a three-dimensional printer may make anexcursion, and the opening 350 may secure the second fixture 342 againstsuch an excursion to facilitate disengaging a coupling between a firstconnector of the extruder and the second connector 344 of the filamenttube 340 to separate the filament tube 340 from the extruder.

The tool rack 300 may define a plurality of openings 350, each opening350 for holding a respective filament tube 340 of a plurality offilament tubes 340. In certain aspects, at least one of the plurality offilament tubes 340 includes a different color filament 302 than anotherone of the plurality of filament tubes 340. Additionally, oralternatively, the filament 302 in at least one of the plurality offilament tubes 340 may have a different material than the filament 302included in another one of the plurality of filament tubes 340.

FIG. 4 is a top view of a tool rack. A tool rack 400 may define anopening 450 and an insertion path 460. The second fixture 442 of afilament tube 440 may be positionable in the opening 450 along theinsertion path 460. The insertion path 460 may be, for example, ahorizontal insertion path (e.g., in the x-y plane of a printer). Itshould be appreciated, however, that the insertion path 460 may, ingeneral, be multi-dimensional. For example, the insertion path 460 mayinclude any number of concurrent or separate movements in the x, y and zdirections. Thus, at least one of the second fixtures 442 may be lockedinto place in the tool rack 400 using a sequence of movements that docksthe second fixture 442 in the tool rack 400 such that the second fixture442 is secure in the opening 450 against dislodgement by a force in anysingle direction. This approach may take a predetermined amount of timeto dock and undock the second fixtures 442. Additionally, oralternatively, this approach can facilitate handling or moving theentire tool rack 400 without dislodging the second fixtures 442.

The tool rack 400 may include a heating element 402 for preheating aplurality of the filament tubes 440 secured in the tool rack 400. Incertain implementations, with the tool rack 400 heated, an end of thefilament tube 440 may further include a gasket or seal to reduce thelikelihood of oozing of melted filament from the filament tube 440. Thesystem may also, or instead, include at least one of a purge wall, apurge receptacle, or a brush for cleaning one or more of the filamenttube 440 and an extruder before, after, or during use. For example, atleast one of a purge wall, a purge receptacle, or a brush may be locatedon the tool rack 400. The tool rack 400, the extruder, or both may alsoor instead include a sensor 404 to detect a presence of one or more ofthe filament tubes 440 included in the tool rack 400.

FIG. 5 is a schematic representation of tool paths of an extruder forfilament swapping in three-dimensional printing. A tool rack 500 maydefine one or more openings 550 and define insertion paths 560 toreceive and secure one or more filament tubes. The shape and structureof the tool rack 500 may, for example, provide for one or more toolpaths of an extruder for filament swapping. For example, the tool rack500 may provide for a first tool path 570 for attaching a filament tubeto an extruder, and a second tool path 580 for detaching a filament tubefrom an extruder.

The first tool path 570 may include a path for positioning the extruderalong the insertion path 560. In certain aspects, the insertion path 560is a horizontal insertion path located at a predetermined height. Thus,for example, a robot that moves the extruder of a three-dimensionalprinter may be movable to position the extruder to receive and secure asecond fixture (with a filament tube) from a predetermined positionbeneath the opening 550 in the tool rack 500, and to move the extruderalong a first axis 562 parallel with the insertion path 560 for exitingthe tool rack 500 with the extruder coupled with the filament tube.Movement along the insertion path 560 may facilitate maintaining acoupling between the extruder and filament tube as the extruder exitsthe tool rack 500. While the extruder may be positioned below thefixture, with the resulting feedpath aligned directed downward toward anobject being fabricated, it will be understood that other arrangementsare additionally, or alternatively, possible. For example, the tool rackmay be configured to store tools vertically or in some otherorientation, and an extruder may be inverted or otherwise rotated offaxis before, during, or after traveling through the insertion path 560.Thus, for example, tools may be stored vertically in a rack with afilament and feedpath horizontally disposed, in which case the extrudermay be rotated about ninety degrees on its axis and then directed towardthe tool rack 500 to engage or disengage one of the fixtures via aninsertion path 560 disposed in a vertical plane. More generally, anyuseful rotational and/or translational orientation of the insertion path560, the extruder, the tool rack 500, and the fixture may be employedwithout departing from the scope of this disclosure.

The second tool path 580 may include an excursion 584 by the extruder(e.g., a robot positioning the extruder) from the insertion path 560 tofacilitate disengaging a coupling between a first connector on theextruder and a second connector on a filament tube to separate thefilament tube from the extruder. The excursion 584 may include, forexample, a horizontal departure from the insertion path 560. Theexcursion 584 may also, or instead, include a vertical departure fromthe insertion path 560. Thus, the robot may position the extruder alongthe insertion path 560 to deposit a second fixture in the opening 550and, further or instead, may move the extruder away from the insertionpath 560 for an excursion 584 to decouple the filament tube from theextruder. The excursion 584 may include movement along a second axis 582that intersects the first axis 562. For example, the second axis 582 maybe substantially perpendicular to the first axis 562.

FIG. 6 is a flow chart of a method for filament swapping inthree-dimensional printing.

As shown in step 604, the method 600 may include securing a filamenttube within an opening defined by a tool rack. This may include securinga plurality of filament tubes within a plurality of respective openingsdefined by the tool rack. The filament tube may be securable in apredetermined alignment with an extruder through a coupling (e.g., amagnetic coupling) between a first connector of the extruder and asecond connector of the filament tube. The predetermined alignment ofthe filament tube and the extruder may define a feed path for thefilament through the filament tube and the extruder.

As shown in step 606, the method 600 may include positioning theextruder beneath the opening defined by the tool rack. For example, theextruder may be positioned such that it is disposed a predetermineddistance beneath the opening defined by the tool rack. At thepredetermined distance, the first connector of the extruder may besecured to the second connector of the filament tube such that thefilament tube is coupled in the predetermined alignment with theextruder.

As shown in step 608, the method 600 may include coupling the filamenttube and the extruder to one another. Such a coupling may include amechanical coupling, such as, for example, a magnetic coupling betweenthe filament tube and the extruder.

As shown in step 610, the method 600 may include exiting the tool rack.Exiting the tool rack may, for example, include moving the extruder,coupled with the filament, tube along an insertion path for exiting thetool rack while maintaining the coupling of the extruder and filamenttube. In certain aspects, by following the insertion path, forces belowa disengagement force of the coupling will be applied to the couplingbetween the extruder and the filament tube such that the extruder andthe filament tube remain coupled to one another as the extruder and thefilament tube are moved along the insertion path.

As shown in step 612, the method 600 may include advancing the filamentthrough the extruder and melting the filament for extrusion through anextrusion port, defined by the extruder, for fabricating an object in athree-dimensional printing process.

As shown in step 614, the method 600 may include retracting the filamentfrom the extruder (e.g., for decoupling of the extruder and the filamenttube). Retracting the filament from the extruder may facilitate, forexample, loading a new filament onto the extruder. In some aspects, amechanical system loads the filament from a filament tube into theextruder using a drive system (e.g., when the extruder couples to thefilament tube or after). Once the extruder is finished fabricating usingthis filament, the filament may be retracted from the extruder tofacilitate loading a new filament. Retraction may occur before theextruder engages the tool rack or after the extruder engages the toolrack. In certain aspects, breaking the coupling of the first connectorand the second connector via an excursion acts to sheer or slice thefilament such that retraction may not be needed.

As shown in step 616, the method 600 may include positioning theextruder, coupled with the filament tube, along the insertion path andinto the opening defined by the tool rack such that a fixture of thefilament tube is in the opening (to deposit the fixture in the opening).

As shown in step 618, the method 600 may include moving the extruder foran excursion, in a direction opposing the insertion path, to decouplethe filament tube from the extruder. The excursion may include one ormore of a horizontal departure from the insertion path and a verticalexcursion from the insertion path. More generally, in this context, adirection “opposing” the insertion path may include any direction thatis constrained by the tool rack such that, for example, the extruder canbe separated from the filament tube.

FIG. 7 is a flow chart of a method for filament swapping inthree-dimensional printing. The method 700 may be in addition to, or asan alternative to, the method recited above with reference to FIG. 6.

As shown in step 702, the method 700 may include positioning theextruder a predetermined distance beneath a second opening defined bythe tool rack to secure the first connector of the extruder with a thirdconnector of a second filament tube such that the second filament tubeis coupled to the extruder. In certain aspects, the second filament isat least one of a different color and material than a filamentpreviously extruded.

As shown in step 704, the method 700 may include coupling the secondfilament tube and the extruder. The coupling may be, for example, anyone or more of the various different couplings described herein.

As shown in step 706, the method 700 may include moving the extruder,coupled with the second filament tube, along a second insertion path forexiting the tool rack while maintaining the coupling of the extruder andsecond filament tube.

As shown in step 708, the method 700 may include advancing a secondfilament through the extruder and melting the second filament forextrusion through the extrusion port as part of a three-dimensionalprinting process for fabricating an object.

The above systems, devices, methods, processes, and the like may be usedin conjunction with, be supplemented by, or otherwise include anextruder with a drive system for feeding two or more filaments. Theabove systems, devices, methods, processes, and the like may also orinstead be used in conjunction with, be supplemented by, or otherwiseinclude a supply-side drive system that feeds filament into the extruderor the filament tubes. In an aspect, the supply-side drive system feedsfilament into the filament tubes in the tool rack, reducing the pullforce required by the drive system of the extruder. For example, eachfilament tube may be associated with its own supply-side drive system.

The above systems, devices, methods, processes, and the like may berealized in hardware, software, or any combination of these suitable forthe control, data acquisition, and data processing described herein.This includes realization in one or more microprocessors,microcontrollers, embedded microcontrollers, programmable digital signalprocessors or other programmable devices or processing circuitry, alongwith internal and/or external memory. This may also, or instead, includeone or more application specific integrated circuits, programmable gatearrays, programmable array logic components, or any other device ordevices that may be configured to process electronic signals. It willfurther be appreciated that a realization of the processes or devicesdescribed above may include computer-executable code created using astructured programming language such as C, an object orientedprogramming language such as C++, or any other high-level or low-levelprogramming language (including assembly languages, hardware descriptionlanguages, and database programming languages and technologies) that maybe stored, compiled or interpreted to run on one of the above devices,as well as heterogeneous combinations of processors, processorarchitectures, or combinations of different hardware and software. Atthe same time, processing may be distributed across devices such as thevarious systems described above, or all of the functionality may beintegrated into a dedicated, standalone device. All such permutationsand combinations are intended to fall within the scope of the presentdisclosure.

Embodiments disclosed herein may include computer program productscomprising computer-executable code or computer-usable code that, whenexecuting on one or more computing devices, performs any and/or all ofthe steps of the control systems described above. The code may be storedin a non-transitory fashion in a computer memory, which may be a memoryfrom which the program executes (such as random access memory associatedwith a processor), or a storage device such as a disk drive, flashmemory or any other optical, electromagnetic, magnetic, infrared orother device or combination of devices. In another aspect, any of thecontrol systems described above may be embodied in any suitabletransmission or propagation medium carrying computer-executable codeand/or any inputs or outputs from same.

The method steps of the implementations described herein are intended toinclude any suitable method of causing such method steps to beperformed, consistent with the patentability of the following claims,unless a different meaning is expressly provided or otherwise clear fromthe context. So for example performing the step of X includes anysuitable method for causing another party such as a remote user, aremote processing resource (e.g., a server or cloud computer) or amachine to perform the step of X. Similarly, performing steps X, Y and Zmay include any method of directing or controlling any combination ofsuch other individuals or resources to perform steps X, Y and Z toobtain the benefit of such steps. Thus method steps of theimplementations described herein are intended to include any suitablemethod of causing one or more other parties or entities to perform thesteps, consistent with the patentability of the following claims, unlessa different meaning is expressly provided or otherwise clear from thecontext. Such parties or entities need not be under the direction orcontrol of any other party or entity, and need not be located within aparticular jurisdiction.

It will be appreciated that the devices, systems, and methods describedabove are set forth by way of example and not of limitation. Numerousvariations, additions, omissions, and other modifications will beapparent to one of ordinary skill in the art. In addition, the order orpresentation of method steps in the description and drawings above isnot intended to require this order of performing the recited stepsunless a particular order is expressly required or otherwise clear fromthe context. Thus, while particular embodiments have been shown anddescribed, it will be apparent to those skilled in the art that variouschanges and modifications in form and details may be made thereinwithout departing from the spirit and scope of this disclosure and areintended to form a part of the invention as defined by the followingclaims, which are to be interpreted in the broadest sense allowable bylaw.

What is claimed is:
 1. A device comprising: an extruder including afirst fixture with a first connector, a drive gear to advance a filamentthrough the extruder, a heat source arranged to melt the filament into amelted state in the extruder, the extruder defining an extrusion portthrough which the filament in the melted state is extrudable; a robotcoupled to the extruder, the robot movable to position the extrudervertically and horizontally in a three-dimensional printing process; afilament tube having a second fixture with a second connector, thesecond connector engageable with the first connector to form a couplingsecuring the filament tube in a predetermined alignment with theextruder to define a feed path for the filament through the filamenttube and the extruder; and a tool rack defining an opening and aninsertion path, the second fixture positionable in the opening along theinsertion path, wherein, when the second fixture is positioned in theopening, the tool rack secures the second fixture against an excursionby the robot from the insertion path to disengage the coupling betweenthe first connector and the second connector to separate the filamenttube from the extruder.
 2. The device of claim 1, wherein the firstconnector includes a first magnet, the second connector includes asecond magnet, and the coupling includes a magnetic coupling between thefirst magnet and the second magnet.
 3. The device of claim 1, whereinthe insertion path is a horizontal insertion path at a predeterminedheight.
 4. The device of claim 3, wherein the excursion of the robotincludes a horizontal departure from the insertion path.
 5. The deviceof claim 3, wherein the excursion of the robot includes a verticaldeparture from the insertion path.
 6. The device of claim 1, wherein thetool rack defines a plurality of openings, each opening sized to hold arespective filament tube of a plurality of filament tubes.
 7. The deviceof claim 6, wherein at least one of the plurality of filament tubesincludes a different color filament than another one of the plurality offilament tubes.
 8. The device of claim 6, wherein at least one of theplurality of filament tubes includes a filament having a differentmaterial than a filament included in another one of the plurality offilament tubes.
 9. The device of claim 6, further comprising a processorconfigured to determine one or more properties of one or more filamentsincluded in the plurality of filament tubes, and to create toolinstructions for fabricating an object using the one or more filamentsbased on the one or more properties.
 10. The device of claim 9, furthercomprising a tag on one or more of a filament spool or a filament tube,the processor configured to determine the one or more properties of theone or more filaments included in the plurality of filament tubes basedon the tag.
 11. The device of claim 1, wherein the robot is configuredto position the extruder to receive and secure the second fixture from apredetermined position beneath the opening in the tool rack and to movethe extruder along a first axis parallel to the insertion path such thatthe extruder exits the tool rack with the extruder coupled with thefilament tube.
 12. The device of claim 11, wherein the robot isconfigured to position the extruder along the insertion path to positionthe second fixture in the opening and to move the extruder away from theinsertion path for an excursion to decouple the filament tube from theextruder.
 13. The device of claim 12, wherein the excursion includesmovement along a second axis intersecting the first axis.
 14. The deviceof claim 13, wherein the second axis is substantially perpendicular tothe first axis.
 15. The device of claim 1, wherein the tool rackincludes a heating element arranged to preheat a plurality of filamenttubes secured in the tool rack.
 16. The device of claim 1, wherein therobot includes an x-y-z positioning system of a three-dimensionalprinter, and wherein the tool rack is within an operating envelope ofthe x-y-z positioning system.
 17. The device of claim 1, furthercomprising a sensor, where a presence of one or more filament tubes inthe tool rack is detectable by the sensor.
 18. A method comprising:securing a filament tube within an opening of a tool rack, the filamenttube securable in a predetermined alignment with an extruder through acoupling between a first connector of the extruder and a secondconnector of the filament tube, the predetermined alignment of thefilament tube and the extruder defining a feed path for a filamentthrough the filament tube and the extruder; positioning the extruder ata predetermined distance beneath the opening defined by the tool rack,where, at the predetermined distance, the first connector of theextruder is secured to the second connector of the filament tube suchthat the filament tube is coupled in the predetermined alignment withthe extruder; moving the extruder, coupled with the filament tube, alongan insertion path for exiting the tool rack while maintaining thecoupling of the extruder and the filament tube; advancing the filamentthrough the extruder and melting the filament for extrusion through anextrusion port defined by the extruder; retracting the filament from theextruder; positioning the extruder, coupled with the filament tube,along the insertion path and into the opening defined by the tool racksuch that a fixture of the filament tube is in the opening; and movingthe extruder, in a direction opposing the insertion path, to decouplethe filament tube from the extruder.
 19. The method of claim 18, furthercomprising: positioning the extruder the predetermined distance beneatha second opening defined by the tool rack to secure the first connectorof the extruder with a third connector of a second filament tube suchthat the second filament tube is coupled with the extruder; moving theextruder, coupled with the second filament tube, along a secondinsertion path for exiting the tool rack while maintaining the couplingof the extruder and second filament tube; and advancing a secondfilament through the extruder and melting the second filament forextrusion through the extrusion port.
 20. The method of claim 18,wherein the direction opposing the insertion path includes one or moreof a horizontal departure from the insertion path and a verticaldeparture from the insertion path.